Various types of swings are well known in the art. Generally, swings include a support frame, a hanger pivotally attached to the support frame, and a seat attached to the hanger. Such devices are designed to swing the seat in a pendulum motion. However, due to frictional loses and wind resistance, additional energy must be supplied to this system in order to maintain an approximately constant amplitude over time. Often manually powered or electrically powered drive mechanisms are utilized to supply the lost energy.
As shown in FIG. 1, one prior art swing, which is commonly assigned to the assignee of the present invention and hereby incorporated by reference, is U.S. Pat. No. 5,525,113 to Mitchell et al. The device to Mitchell et al. is a swing assembly that includes a swing drive mechanism (10). The swing drive mechanism (10) has a drive sleeve (12) rotatably mounted to an axle (14) that operatively supports the hanger, not shown. A drive flange (16) is mounted on the axle (14) with a drive flange coupling device (18) positioned between the drive sleeve (12) and the drive flange (16) to provide a limited lost motion connection. The drive flange coupling device (18) includes a hub member (20) coaxially and rotatably mounted on the axle (14) and at least one torsion spring, shown as a pair of torsion springs (24a, 24b), mounted coaxially on the hub member (20). A crank, not shown, driven by a motor, not shown, is commonly linked to the drive sleeve (12) through a channel (26) to oscillate the drive sleeve (12) .
Although the above disclosed device has substantially advanced the art, it has been found that further advancements could still be made. For instance, the swing drive mechanism to Mitchell et al. has at a minimum a total of six parts: the drive sleeve (12), the pair of torsion springs 24(a) and 24(b), the hub member (20), the drive flange (16), and the axle (14). Further, the swing drive mechanism (10) requires additional mechanisms to couple the swing drive mechanism (10) with the hub, not shown. In addition, other mechanisms are needed to secure the drive sleeve (12), the torsion springs (24a, 24b), the hub member (20), and the drive flange (16) on axle (14).
Secondly, although the device to Mitchell et al. provides superior performance over other swing drive mechanisms, it has been found that the assembly operation of such devices is somewhat complicated. Accordingly, the various elements are prone to being misassembled. As such, it would be desirable to provide a swing drive mechanism that maintains the superior performance as disclosed in Mitchell et al. while also being configured to simplify the assembly operation and minimize the opportunity for misassembly.
In light of the above, one skilled in the art can appreciate that it would be desirable to provide a swing drive mechanism that minimizes frictional loses and minimizes the overall size of swing drive mechanisms. However, in addition, it would also be desirable to have a swing drive mechanism that reduces the overall number of parts required as well as reduce the opportunity for misassembly.